Conventional methods of traffic control and road construction of road intersections cause many instances of traffic interruption which in turn cause vehicular accidents or blockage of the road by vehicles at such intersections.
One approach to solving the above traffic interruption problems is set out in the present Applicant's U.S. Pat. No. 4,986,692 relating to road intersection construction for traffic control. There is described therein a safety island provided longitudinally parallel to the main road at the center line of the intersection. The safety island prevents vehicles from the branch road from crossing the intersection. Circular detour roads beneath or above the main road are provided for traffic circulation. Underground passages for motorcycles and pedestrians may be provided beneath the intersection to eliminate interference with car traffic. Cars on the inner lane of the main roadway can then proceed through the intersection without interruption. In particular, U.S. Pat. No. 4,986,692 teaches the provision of a pair of opposed circular detour roads disposed on either side of said intersection, each detour road having an entrance opening off of the outside lane of the main road an exit onto the outside lane thereof proceeding in the opposite direction with each outside lane having an entrance on one side of the intersection and an exit on the other.
However, although the road intersection construction set out in U.S. Pat. No. 4,986,692 may be eminently suitable for a rural environment where land space is not necessarily at a premium, and vehicle speeds on the main road and the detour roads tend to be relatively high, it is unsuitable for an urban environment where vehicular speeds tend to be lower and efficient utilization of land space is regarded as being of great importance.
Furthermore, the complications of traffic noise, air pollution, vehicle accidents, and congestion in the vicinity of and on a complex road intersection system in an urban environment frequently render the appearance of such an intersection system visually unattractive.
It is, therefore, an objective of the present invention to provide an improvement to the road intersection construction of U.S. Pat. No. 4,986,692 wherein efficient utilization of land space is maximized. It is also another objective of the present invention to integrate a road intersection construction as far as possible into an urban environment in an attractive manner, both visually and with respect to air and noise pollution.